xref: /dragonfly/sys/dev/netif/plip/if_plip.c (revision 1bf4b486)
1 /*-
2  * Copyright (c) 1997 Poul-Henning Kamp
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  *	From Id: lpt.c,v 1.55.2.1 1996/11/12 09:08:38 phk Exp
27  * $FreeBSD: src/sys/dev/ppbus/if_plip.c,v 1.19.2.1 2000/05/24 00:20:57 n_hibma Exp $
28  * $DragonFly: src/sys/dev/netif/plip/if_plip.c,v 1.12 2005/06/13 14:00:29 joerg Exp $
29  */
30 
31 /*
32  * Parallel port TCP/IP interfaces added.  I looked at the driver from
33  * MACH but this is a complete rewrite, and btw. incompatible, and it
34  * should perform better too.  I have never run the MACH driver though.
35  *
36  * This driver sends two bytes (0x08, 0x00) in front of each packet,
37  * to allow us to distinguish another format later.
38  *
39  * Now added an Linux/Crynwr compatibility mode which is enabled using
40  * IF_LINK0 - Tim Wilkinson.
41  *
42  * TODO:
43  *    Make HDLC/PPP mode, use IF_LLC1 to enable.
44  *
45  * Connect the two computers using a Laplink parallel cable to use this
46  * feature:
47  *
48  *      +----------------------------------------+
49  * 	|A-name	A-End	B-End	Descr.	Port/Bit |
50  *      +----------------------------------------+
51  *	|DATA0	2	15	Data	0/0x01   |
52  *	|-ERROR	15	2	   	1/0x08   |
53  *      +----------------------------------------+
54  *	|DATA1	3	13	Data	0/0x02	 |
55  *	|+SLCT	13	3	   	1/0x10   |
56  *      +----------------------------------------+
57  *	|DATA2	4	12	Data	0/0x04   |
58  *	|+PE	12	4	   	1/0x20   |
59  *      +----------------------------------------+
60  *	|DATA3	5	10	Strobe	0/0x08   |
61  *	|-ACK	10	5	   	1/0x40   |
62  *      +----------------------------------------+
63  *	|DATA4	6	11	Data	0/0x10   |
64  *	|BUSY	11	6	   	1/~0x80  |
65  *      +----------------------------------------+
66  *	|GND	18-25	18-25	GND	-        |
67  *      +----------------------------------------+
68  *
69  * Expect transfer-rates up to 75 kbyte/sec.
70  *
71  * If GCC could correctly grok
72  *	register int port asm("edx")
73  * the code would be cleaner
74  *
75  * Poul-Henning Kamp <phk@freebsd.org>
76  */
77 
78 /*
79  * Update for ppbus, PLIP support only - Nicolas Souchu
80  */
81 
82 #include "opt_plip.h"
83 
84 #include <sys/param.h>
85 #include <sys/systm.h>
86 #include <sys/module.h>
87 #include <sys/bus.h>
88 #include <sys/mbuf.h>
89 #include <sys/socket.h>
90 #include <sys/sockio.h>
91 #include <sys/kernel.h>
92 #include <sys/malloc.h>
93 #include <sys/thread2.h>
94 
95 #include <machine/clock.h>
96 #include <machine/bus.h>
97 #include <machine/resource.h>
98 #include <sys/rman.h>
99 
100 #include <net/if.h>
101 #include <net/ifq_var.h>
102 #include <net/if_types.h>
103 #include <net/netisr.h>
104 
105 #include <netinet/in.h>
106 #include <netinet/in_var.h>
107 
108 #include <net/bpf.h>
109 
110 #include <bus/ppbus/ppbconf.h>
111 #include "ppbus_if.h"
112 #include <bus/ppbus/ppbio.h>
113 
114 #ifndef LPMTU			/* MTU for the lp# interfaces */
115 #define	LPMTU	1500
116 #endif
117 
118 #ifndef LPMAXSPIN1		/* DELAY factor for the lp# interfaces */
119 #define	LPMAXSPIN1	8000   /* Spinning for remote intr to happen */
120 #endif
121 
122 #ifndef LPMAXSPIN2		/* DELAY factor for the lp# interfaces */
123 #define	LPMAXSPIN2	500	/* Spinning for remote handshake to happen */
124 #endif
125 
126 #ifndef LPMAXERRS		/* Max errors before !RUNNING */
127 #define	LPMAXERRS	100
128 #endif
129 
130 #define CLPIPHDRLEN	14	/* We send dummy ethernet addresses (two) + packet type in front of packet */
131 #define	CLPIP_SHAKE	0x80	/* This bit toggles between nibble reception */
132 #define MLPIPHDRLEN	CLPIPHDRLEN
133 
134 #define LPIPHDRLEN	2	/* We send 0x08, 0x00 in front of packet */
135 #define	LPIP_SHAKE	0x40	/* This bit toggles between nibble reception */
136 #if !defined(MLPIPHDRLEN) || LPIPHDRLEN > MLPIPHDRLEN
137 #define MLPIPHDRLEN	LPIPHDRLEN
138 #endif
139 
140 #define	LPIPTBLSIZE	256	/* Size of octet translation table */
141 
142 #define lprintf		if (lptflag) printf
143 
144 #ifdef PLIP_DEBUG
145 static int volatile lptflag = 1;
146 #else
147 static int volatile lptflag = 0;
148 #endif
149 
150 struct lp_data {
151 	unsigned short lp_unit;
152 
153 	struct  ifnet	sc_if;
154 	u_char		*sc_ifbuf;
155 	int		sc_iferrs;
156 
157 	struct resource *res_irq;
158 };
159 
160 /* Tables for the lp# interface */
161 static u_char *txmith;
162 #define txmitl (txmith+(1*LPIPTBLSIZE))
163 #define trecvh (txmith+(2*LPIPTBLSIZE))
164 #define trecvl (txmith+(3*LPIPTBLSIZE))
165 
166 static u_char *ctxmith;
167 #define ctxmitl (ctxmith+(1*LPIPTBLSIZE))
168 #define ctrecvh (ctxmith+(2*LPIPTBLSIZE))
169 #define ctrecvl (ctxmith+(3*LPIPTBLSIZE))
170 
171 /* Functions for the lp# interface */
172 static int lpinittables(void);
173 static int lpioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
174 static int lpoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
175 	struct rtentry *);
176 static void lp_intr(void *);
177 
178 #define DEVTOSOFTC(dev) \
179 	((struct lp_data *)device_get_softc(dev))
180 #define UNITOSOFTC(unit) \
181 	((struct lp_data *)devclass_get_softc(lp_devclass, (unit)))
182 #define UNITODEVICE(unit) \
183 	(devclass_get_device(lp_devclass, (unit)))
184 
185 static devclass_t lp_devclass;
186 
187 static void
188 lp_identify(driver_t *driver, device_t parent)
189 {
190 
191 	BUS_ADD_CHILD(parent, 0, "plip", 0);
192 }
193 /*
194  * lpprobe()
195  */
196 static int
197 lp_probe(device_t dev)
198 {
199 	device_t ppbus = device_get_parent(dev);
200 	struct lp_data *lp;
201 	int zero = 0;
202 	uintptr_t irq;
203 
204 	lp = DEVTOSOFTC(dev);
205 	bzero(lp, sizeof(struct lp_data));
206 
207 	/* retrieve the ppbus irq */
208 	BUS_READ_IVAR(ppbus, dev, PPBUS_IVAR_IRQ, &irq);
209 
210 	/* if we haven't interrupts, the probe fails */
211 	if (irq == -1) {
212 		device_printf(dev, "not an interrupt driven port, failed.\n");
213 		return (ENXIO);
214 	}
215 
216 	/* reserve the interrupt resource, expecting irq is available to continue */
217 	lp->res_irq = bus_alloc_resource(dev, SYS_RES_IRQ, &zero, irq, irq, 1,
218 					 RF_SHAREABLE);
219 	if (lp->res_irq == 0) {
220 		device_printf(dev, "cannot reserve interrupt, failed.\n");
221 		return (ENXIO);
222 	}
223 
224 	/*
225 	 * lp dependent initialisation.
226 	 */
227 	lp->lp_unit = device_get_unit(dev);
228 
229 	device_set_desc(dev, "PLIP network interface");
230 
231 	return (0);
232 }
233 
234 static int
235 lp_attach (device_t dev)
236 {
237 	struct lp_data *lp = DEVTOSOFTC(dev);
238 	struct ifnet *ifp = &lp->sc_if;
239 
240 	ifp->if_softc = lp;
241 	if_initname(ifp, "lp", device_get_unit(dev));
242 	ifp->if_mtu = LPMTU;
243 	ifp->if_flags = IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST;
244 	ifp->if_ioctl = lpioctl;
245 	ifp->if_output = lpoutput;
246 	ifp->if_type = IFT_PARA;
247 	ifp->if_hdrlen = 0;
248 	ifp->if_addrlen = 0;
249 	ifq_set_maxlen(&ifp->if_snd, IFQ_MAXLEN);
250 	if_attach(ifp);
251 
252 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
253 
254 	return (0);
255 }
256 /*
257  * Build the translation tables for the LPIP (BSD unix) protocol.
258  * We don't want to calculate these nasties in our tight loop, so we
259  * precalculate them when we initialize.
260  */
261 static int
262 lpinittables (void)
263 {
264     int i;
265 
266     if (!txmith)
267 	txmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
268 
269     if (!ctxmith)
270 	ctxmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
271 
272     for (i=0; i < LPIPTBLSIZE; i++) {
273 	ctxmith[i] = (i & 0xF0) >> 4;
274 	ctxmitl[i] = 0x10 | (i & 0x0F);
275 	ctrecvh[i] = (i & 0x78) << 1;
276 	ctrecvl[i] = (i & 0x78) >> 3;
277     }
278 
279     for (i=0; i < LPIPTBLSIZE; i++) {
280 	txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
281 	txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
282 	trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
283 	trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
284     }
285 
286     return 0;
287 }
288 
289 /*
290  * Process an ioctl request.
291  */
292 
293 static int
294 lpioctl (struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
295 {
296     device_t dev = UNITODEVICE(ifp->if_dunit);
297     device_t ppbus = device_get_parent(dev);
298     struct lp_data *sc = DEVTOSOFTC(dev);
299     struct ifaddr *ifa = (struct ifaddr *)data;
300     struct ifreq *ifr = (struct ifreq *)data;
301     u_char *ptr;
302     void *ih;
303     int error;
304 
305     switch (cmd) {
306 
307     case SIOCSIFDSTADDR:
308     case SIOCAIFADDR:
309     case SIOCSIFADDR:
310 	if (ifa->ifa_addr->sa_family != AF_INET)
311 	    return EAFNOSUPPORT;
312 
313 	ifp->if_flags |= IFF_UP;
314 	/* FALLTHROUGH */
315     case SIOCSIFFLAGS:
316 	if ((!(ifp->if_flags & IFF_UP)) && (ifp->if_flags & IFF_RUNNING)) {
317 
318 	    ppb_wctr(ppbus, 0x00);
319 	    ifp->if_flags &= ~IFF_RUNNING;
320 
321 	    /* IFF_UP is not set, try to release the bus anyway */
322 	    ppb_release_bus(ppbus, dev);
323 	    break;
324 	}
325 	if (((ifp->if_flags & IFF_UP)) && (!(ifp->if_flags & IFF_RUNNING))) {
326 
327 	    /* XXX
328 	     * Should the request be interruptible?
329 	     */
330 	    if ((error = ppb_request_bus(ppbus, dev, PPB_WAIT|PPB_INTR)))
331 		return (error);
332 
333 	    /* Now IFF_UP means that we own the bus */
334 
335 	    ppb_set_mode(ppbus, PPB_COMPATIBLE);
336 
337 	    if (lpinittables()) {
338 		ppb_release_bus(ppbus, dev);
339 		return ENOBUFS;
340 	    }
341 
342 	    sc->sc_ifbuf = malloc(sc->sc_if.if_mtu + MLPIPHDRLEN,
343 				  M_DEVBUF, M_WAITOK);
344 	    if (!sc->sc_ifbuf) {
345 		ppb_release_bus(ppbus, dev);
346 		return ENOBUFS;
347 	    }
348 
349 	    /* attach our interrupt handler, later detached when the bus is released */
350 	    error = BUS_SETUP_INTR(ppbus, dev, sc->res_irq, INTR_TYPE_NET,
351 				   lp_intr, dev, &ih, NULL);
352 	    if (error) {
353 		ppb_release_bus(ppbus, dev);
354 		return (error);
355 	    }
356 
357 	    ppb_wctr(ppbus, IRQENABLE);
358 	    ifp->if_flags |= IFF_RUNNING;
359 	}
360 	break;
361 
362     case SIOCSIFMTU:
363 	ptr = sc->sc_ifbuf;
364 	sc->sc_ifbuf = malloc(ifr->ifr_mtu+MLPIPHDRLEN, M_DEVBUF, M_WAITOK);
365 	if (ptr)
366 	    free(ptr,M_DEVBUF);
367 	sc->sc_if.if_mtu = ifr->ifr_mtu;
368 	break;
369 
370     case SIOCGIFMTU:
371 	ifr->ifr_mtu = sc->sc_if.if_mtu;
372 	break;
373 
374     case SIOCADDMULTI:
375     case SIOCDELMULTI:
376 	if (ifr == 0) {
377 	    return EAFNOSUPPORT;		/* XXX */
378 	}
379 	switch (ifr->ifr_addr.sa_family) {
380 
381 	case AF_INET:
382 	    break;
383 
384 	default:
385 	    return EAFNOSUPPORT;
386 	}
387 	break;
388 
389     case SIOCGIFMEDIA:
390 	/*
391 	 * No ifmedia support at this stage; maybe use it
392 	 * in future for eg. protocol selection.
393 	 */
394 	return EINVAL;
395 
396     default:
397 	lprintf("LP:ioctl(0x%lx)\n", cmd);
398 	return EINVAL;
399     }
400     return 0;
401 }
402 
403 static __inline int
404 clpoutbyte (u_char byte, int spin, device_t ppbus)
405 {
406 	ppb_wdtr(ppbus, ctxmitl[byte]);
407 	while (ppb_rstr(ppbus) & CLPIP_SHAKE)
408 		if (--spin == 0) {
409 			return 1;
410 		}
411 	ppb_wdtr(ppbus, ctxmith[byte]);
412 	while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
413 		if (--spin == 0) {
414 			return 1;
415 		}
416 	return 0;
417 }
418 
419 static __inline int
420 clpinbyte (int spin, device_t ppbus)
421 {
422 	u_char c, cl;
423 
424 	while((ppb_rstr(ppbus) & CLPIP_SHAKE))
425 	    if(!--spin) {
426 		return -1;
427 	    }
428 	cl = ppb_rstr(ppbus);
429 	ppb_wdtr(ppbus, 0x10);
430 
431 	while(!(ppb_rstr(ppbus) & CLPIP_SHAKE))
432 	    if(!--spin) {
433 		return -1;
434 	    }
435 	c = ppb_rstr(ppbus);
436 	ppb_wdtr(ppbus, 0x00);
437 
438 	return (ctrecvl[cl] | ctrecvh[c]);
439 }
440 
441 static void
442 lptap(struct ifnet *ifp, struct mbuf *m)
443 {
444 	/*
445 	 * We need to prepend the address family as a four byte field.
446 	 */
447 	static const uint32_t af = AF_INET;
448 
449 	if (ifp->if_bpf)
450 		bpf_ptap(ifp->if_bpf, m, &af, sizeof(af));
451 }
452 
453 static void
454 lp_intr (void *arg)
455 {
456 	device_t dev = (device_t)arg;
457         device_t ppbus = device_get_parent(dev);
458 	struct lp_data *sc = DEVTOSOFTC(dev);
459 	int len, j;
460 	u_char *bp;
461 	u_char c, cl;
462 	struct mbuf *top;
463 
464 	crit_enter();
465 
466 	if (sc->sc_if.if_flags & IFF_LINK0) {
467 
468 	    /* Ack. the request */
469 	    ppb_wdtr(ppbus, 0x01);
470 
471 	    /* Get the packet length */
472 	    j = clpinbyte(LPMAXSPIN2, ppbus);
473 	    if (j == -1)
474 		goto err;
475 	    len = j;
476 	    j = clpinbyte(LPMAXSPIN2, ppbus);
477 	    if (j == -1)
478 		goto err;
479 	    len = len + (j << 8);
480 	    if (len > sc->sc_if.if_mtu + MLPIPHDRLEN)
481 		goto err;
482 
483 	    bp  = sc->sc_ifbuf;
484 
485 	    while (len--) {
486 	        j = clpinbyte(LPMAXSPIN2, ppbus);
487 	        if (j == -1) {
488 		    goto err;
489 	        }
490 	        *bp++ = j;
491 	    }
492 	    /* Get and ignore checksum */
493 	    j = clpinbyte(LPMAXSPIN2, ppbus);
494 	    if (j == -1) {
495 	        goto err;
496 	    }
497 
498 	    len = bp - sc->sc_ifbuf;
499 	    if (len <= CLPIPHDRLEN)
500 	        goto err;
501 
502 	    sc->sc_iferrs = 0;
503 
504 	    len -= CLPIPHDRLEN;
505 	    sc->sc_if.if_ipackets++;
506 	    sc->sc_if.if_ibytes += len;
507 	    top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, &sc->sc_if, 0);
508 	    if (top) {
509 		if (sc->sc_if.if_bpf)
510 		    lptap(&sc->sc_if, top);
511 		netisr_queue(NETISR_IP, top);
512 	    }
513 	    goto done;
514 	}
515 	while ((ppb_rstr(ppbus) & LPIP_SHAKE)) {
516 	    len = sc->sc_if.if_mtu + LPIPHDRLEN;
517 	    bp  = sc->sc_ifbuf;
518 	    while (len--) {
519 
520 		cl = ppb_rstr(ppbus);
521 		ppb_wdtr(ppbus, 8);
522 
523 		j = LPMAXSPIN2;
524 		while((ppb_rstr(ppbus) & LPIP_SHAKE))
525 		    if(!--j) goto err;
526 
527 		c = ppb_rstr(ppbus);
528 		ppb_wdtr(ppbus, 0);
529 
530 		*bp++= trecvh[cl] | trecvl[c];
531 
532 		j = LPMAXSPIN2;
533 		while (!((cl=ppb_rstr(ppbus)) & LPIP_SHAKE)) {
534 		    if (cl != c &&
535 			(((cl = ppb_rstr(ppbus)) ^ 0xb8) & 0xf8) ==
536 			  (c & 0xf8))
537 			goto end;
538 		    if (!--j) goto err;
539 		}
540 	    }
541 
542 	end:
543 	    len = bp - sc->sc_ifbuf;
544 	    if (len <= LPIPHDRLEN)
545 		goto err;
546 
547 	    sc->sc_iferrs = 0;
548 
549 	    len -= LPIPHDRLEN;
550 	    sc->sc_if.if_ipackets++;
551 	    sc->sc_if.if_ibytes += len;
552 	    top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, &sc->sc_if, 0);
553 	    if (top) {
554 		if (sc->sc_if.if_bpf)
555 		    lptap(&sc->sc_if, top);
556 		netisr_queue(NETISR_IP, top);
557 	    }
558 	}
559 	goto done;
560 
561     err:
562 	ppb_wdtr(ppbus, 0);
563 	lprintf("R");
564 	sc->sc_if.if_ierrors++;
565 	sc->sc_iferrs++;
566 
567 	/*
568 	 * We are not able to send receive anything for now,
569 	 * so stop wasting our time
570 	 */
571 	if (sc->sc_iferrs > LPMAXERRS) {
572 	    printf("lp%d: Too many errors, Going off-line.\n", device_get_unit(dev));
573 	    ppb_wctr(ppbus, 0x00);
574 	    sc->sc_if.if_flags &= ~IFF_RUNNING;
575 	    sc->sc_iferrs=0;
576 	}
577 
578     done:
579 	crit_exit();
580 	return;
581 }
582 
583 static __inline int
584 lpoutbyte (u_char byte, int spin, device_t ppbus)
585 {
586     ppb_wdtr(ppbus, txmith[byte]);
587     while (!(ppb_rstr(ppbus) & LPIP_SHAKE))
588 	if (--spin == 0)
589 		return 1;
590     ppb_wdtr(ppbus, txmitl[byte]);
591     while (ppb_rstr(ppbus) & LPIP_SHAKE)
592 	if (--spin == 0)
593 		return 1;
594     return 0;
595 }
596 
597 static int
598 lpoutput (struct ifnet *ifp, struct mbuf *m,
599 	  struct sockaddr *dst, struct rtentry *rt)
600 {
601     device_t dev = UNITODEVICE(ifp->if_dunit);
602     device_t ppbus = device_get_parent(dev);
603     int err;
604     struct mbuf *mm;
605     u_char *cp = "\0\0";
606     u_char chksum = 0;
607     int count = 0;
608     int i, len, spin;
609 
610     /* We need a sensible value if we abort */
611     cp++;
612     ifp->if_flags |= IFF_RUNNING;
613 
614     err = 1;			/* assume we're aborting because of an error */
615 
616     crit_enter();
617 
618     /* Suspend (on laptops) or receive-errors might have taken us offline */
619     ppb_wctr(ppbus, IRQENABLE);
620 
621     if (ifp->if_flags & IFF_LINK0) {
622 
623 	if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
624 	    lprintf("&");
625 	    lp_intr(dev);
626 	}
627 
628 	/* Alert other end to pending packet */
629 	spin = LPMAXSPIN1;
630 	ppb_wdtr(ppbus, 0x08);
631 	while ((ppb_rstr(ppbus) & 0x08) == 0)
632 		if (--spin == 0) {
633 			goto nend;
634 		}
635 
636 	/* Calculate length of packet, then send that */
637 
638 	count += 14;		/* Ethernet header len */
639 
640 	mm = m;
641 	for (mm = m; mm; mm = mm->m_next) {
642 		count += mm->m_len;
643 	}
644 	if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
645 		goto nend;
646 	if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
647 		goto nend;
648 
649 	/* Send dummy ethernet header */
650 	for (i = 0; i < 12; i++) {
651 		if (clpoutbyte(i, LPMAXSPIN1, ppbus))
652 			goto nend;
653 		chksum += i;
654 	}
655 
656 	if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
657 		goto nend;
658 	if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
659 		goto nend;
660 	chksum += 0x08 + 0x00;		/* Add into checksum */
661 
662 	mm = m;
663 	do {
664 		cp = mtod(mm, u_char *);
665 		len = mm->m_len;
666 		while (len--) {
667 			chksum += *cp;
668 			if (clpoutbyte(*cp++, LPMAXSPIN2, ppbus))
669 				goto nend;
670 		}
671 	} while ((mm = mm->m_next));
672 
673 	/* Send checksum */
674 	if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
675 		goto nend;
676 
677 	/* Go quiescent */
678 	ppb_wdtr(ppbus, 0);
679 
680 	err = 0;			/* No errors */
681 
682 	nend:
683 	if (err)  {				/* if we didn't timeout... */
684 		ifp->if_oerrors++;
685 		lprintf("X");
686 	} else {
687 		ifp->if_opackets++;
688 		ifp->if_obytes += m->m_pkthdr.len;
689 		if (ifp->if_bpf)
690 		    lptap(ifp, m);
691 	}
692 
693 	m_freem(m);
694 
695 	if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
696 		lprintf("^");
697 		lp_intr(dev);
698 	}
699 	crit_exit();
700 	return 0;
701     }
702 
703     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
704         lprintf("&");
705         lp_intr(dev);
706     }
707 
708     if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
709         goto end;
710     if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
711         goto end;
712 
713     mm = m;
714     do {
715         cp = mtod(mm,u_char *);
716 	len = mm->m_len;
717         while (len--)
718 	    if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
719 	        goto end;
720     } while ((mm = mm->m_next));
721 
722     err = 0;				/* no errors were encountered */
723 
724     end:
725     --cp;
726     ppb_wdtr(ppbus, txmitl[*cp] ^ 0x17);
727 
728     if (err)  {				/* if we didn't timeout... */
729 	ifp->if_oerrors++;
730         lprintf("X");
731     } else {
732 	ifp->if_opackets++;
733 	ifp->if_obytes += m->m_pkthdr.len;
734 	if (ifp->if_bpf)
735 	    lptap(ifp, m);
736     }
737 
738     m_freem(m);
739 
740     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
741 	lprintf("^");
742 	lp_intr(dev);
743     }
744 
745     crit_exit();
746     return 0;
747 }
748 
749 static device_method_t lp_methods[] = {
750   	/* device interface */
751 	DEVMETHOD(device_identify,	lp_identify),
752 	DEVMETHOD(device_probe,		lp_probe),
753 	DEVMETHOD(device_attach,	lp_attach),
754 
755 	{ 0, 0 }
756 };
757 
758 static driver_t lp_driver = {
759   "plip",
760   lp_methods,
761   sizeof(struct lp_data),
762 };
763 
764 DECLARE_DUMMY_MODULE(if_plip);
765 DRIVER_MODULE(if_plip, ppbus, lp_driver, lp_devclass, 0, 0);
766 
767